Parasternal nodes

At a glance

English

Parasternal nodes

Latin (TA2)

Nodi parasternales

System

Lymphatic

Region

Whole body

Side

Paired, left and right

About the parasternal nodes

The parasternal nodes, also called the internal thoracic or internal mammary nodes, form a vertical chain on each side of the sternum. They lie at the front ends of the intercostal spaces, deep to the costal cartilages and the intercostal muscles, alongside the internal thoracic artery and its veins. Behind them is the thin transversus thoracis muscle and then the parietal pleura. They are usually found in the upper three or four spaces, with one or two nodes in each.

They are the anterior counterparts of the intercostal nodes at the back of the chest. Between the two chains, the deep lymph of the thoracic wall is shared out by position: front to the parasternal nodes, back to the intercostal nodes.

Lymph reaches them from several directions. They take vessels from the inner part of the breast, from the deep tissues of the front of the chest wall, and from the deeper layers of the front abdominal wall down to the umbilicus, which climb with the superior epigastric vessels. From the liver's convex upper face, lymph arrives through a small group of nodes behind the xiphoid process. The efferent vessels on each side usually join into one trunk. This may empty at the venous angle where the internal jugular vein meets the subclavian, or join the bronchomediastinal trunk; on the right it may enter the right subclavian trunk, and on the left the thoracic duct. Some lymph also passes to the brachiocephalic nodes.

Their main clinical importance is in breast cancer, particularly tumours in the inner half of the breast, which may spread here without passing through the axilla. Disease in this chain changes staging and treatment and may be included in a radiotherapy field. Because the two chains connect across the midline behind the sternum, cancer from one side can reach the other. They may also enlarge in lymphoma and in liver or upper abdominal disease.

Course and drainage

Begins at

Afferent vessels from the inner part of the breast, the deep anterior chest wall, the deep front abdominal wall down to the umbilicus, and the convex top of the liver via the nodes behind the xiphoid process.

Drains into

Efferent vessels form one trunk on each side, ending at the venous angle of the neck or in the bronchomediastinal trunk, the right subclavian trunk or, on the left, the thoracic duct.

Drains

Filters lymph from the front of the chest and upper abdominal wall, the medial breast and the top of the liver. A route by which inner breast cancer bypasses the axilla.